Apparatus for coating magnet wire and the like



V. H. LAUSEN June 26, 1962 APPARATUS FOR COATING MAGNET WIRE AND THE LIKE 4 Sheets-Sheet 1 Filed April 25, 1961 INVENTOR. VERNE' H. LAUSEN ATTORNEYS.

v. H. I AusEN 3,040,703

June 26, 1962 APPARATUS FOR COATING MAGNET WIRE AND THE LIKE 4 Sheets-Sheet 2 Filed April 25, 1961 VEQNE H. LA usf/v VWM IMA

June 26, 1962 v H I AUsI-:N

APPARATUS FoR coATING MAGNET WIRE AND THE LIKE Flled Aprll 25 1961 3 wor. fol @0C n A 3 Ru v E 7, m mm.. f m 0 S 7 4 Q Maw r 0 t I 3, m M. V s R f 4 W NNN H ,A w w y AA: l.

June 26, 1962 v. H. LAUSEN I 3,040,703

APPARATUS FOR COATING MAGNET WIRE AND TRE: LIKE Filed April 25, 1961 i 4 Sheets-Sheet 4 v IZ 54a Ma Pl! FIGIO F|G.l

INVEN TOR. VEQNE H. LA USL-'N BYOQv/wv, F VWM 4 TmQA/EYS.

This invention relates to apparatus for coating wire, as

' in the production of magnet wire, and has particular reference to an improved wire coating apparatus of the type including an oven through which the wire is moved lengthwise in multiple passes back and forth from one end of the oven to the other, and applicator means located at one or both ends of the oven for coating the wire with a coating liquid or with two different coating liquids.

In cases where magnet wire is to be provided with multiple coatings of two dierent film-forming liquids, such apparatus as used hereto-fore has included two applicators, one at each end of the oven, for applying the respective liquids to the wire. For example, the applicator at the front end of the oven applies two or more coatings of a dielectric undercoating liquid while the applicator at the rear end applies two or more rcoatings of a finish coating liquid, each coating from each applicator being dried or cured by movement of 'the corresponding wire pass through the oven before application of the next coating. This requires that the wire bypass the rear applicator while picking up the necessary number of dielectric coatings for the proper dielectric build on the wire, and that the wire then bypass the front applicator while picking up the proper number of finish coatings on its way to the usual vvindup reel or spool. Thus, the passes of the wire through the oven in returning to an applicator, for another coating of the corresponding liquid over a similar coating previously applied by such applicator, are useless or dry passes, as each coating from` Such applicator is dried or cured when it first passes through the oven. These useless return passes substantially reduce the oven capacity in the application of two different coating materials tto the wire, as compared with its capacity when the same total number of coats of a single material are applied from applicators at both ends of the oven.

The principal object of the present invention is to provide a wire coating apparatus of the character described which overcomes the above-noted disadvantage of useless return passes and reduced oven capacity'when applying different coating materials to the same wire. A further object is to provide such an apparatus which is adiustable to vary the number of coatings of each of the two different coating materials to be applied to the wire, and

which is adapted for coating the wire with two or more different materials and with all liquid coatings receiving identical exposure in the oven.

A wire coating apparatus made according to the invention comprises a pair of coating applicators located adjacent the oven at one end thereof and each including a block having a channel disposed below a series of wire passes moving to the oven, and means for supplying two different coating liquids to therespective applicator channels, each applicator including at least one die for applying the corresponding coating liquid to a selected pass of the series which is not coated by a die of the other applicator and also including spacer means forming a space for movement of each pass of the series which is coated by a die of the other applicator. In this way, each pass of the series receives a coating from one of the two appli- -cators and by-passes the other applicator. With the use of only one pair of such applicators as described, each coating applied to the wire from an applicator will move through the oven twice (once to the far end of the oven Patented June 26, 1962 and again back to the applicators for the next coating) before application of the next coating, which may be desirable in cases where the coatings cannot be sufficiently dried or cured in a single pass through the oven. However, even in such cases the use of the dual applicators at one end of the oven will cause all of the liquid coatings to receive identical exposure in the oven, contrary to the situation in which the two applicators are located at opposite ends of the oven. .p

The apparatus in its preferred form comprises a pair of coating Vapplicators located at each end of the oven, the applicators of each pair being positioned to apply coating liquid to an overlying series of the wire passes moving to the oven, pipes leading to one applicator of each pair for supplying thereto a first coatingY liquid, and pipes leading to the other applicator of each pair for supplying thereto a second coating liquid. Each applicator of each pair includes at least one die for applying a coating of the corresponding liquid to a wire pass of the corresponding series and forms a bypass space for passage of each wire pass coated by a die ofthe other applicator of this pair. Accordingly, each coating applied to the wire will pass through the oven only once before application o-f the next coating, whether this next coating be of the same material as the previous coating or of a diderent material, and each pass moving in either direction through the oven will have received a liquid coating from an applicator of one pair either before or after bypassing the other applicator of such pair.

in its preferred construction, each applicator includes a driven shaft extending along the corresponding liquid supply channel above the bottom thereof, and a trough mounted in the channel and providedwith a series of holes spaced along the channel. Each die of the applicator is in the form of a circular disc provided with a circumferential groove `for supplying the film-forming liquid coating to the wire, the bottom of this groove being formed with a smaller circumferential groove through which the wire moves and which is triangular in cross-section and dimensioned to determine the thickness of the film deposited on the wire. Each disc or die is mounted on and rotated by the shaft with the lower portion of the disc fitting closely in the trough and with the die groove overlying one of the holes in the trough through which liquid is supplied to this groove from the channel. Rotation of the die applies a continuous and complete coating of the liquid to a corresponding pass of the wire moving over the die through its groove. The shaft is preferably provided also with vspacer means located on those portions of the shaft not occupied by, the die or `dies and which permit bypassing of the applicator by the pass or passes of the corresponding series receiving a coating from the companion applicator of the corresponding pair.

Plug means are preferably provided in each applicator trough to substantially fill those portions of the trough not occupied by the die or dies, thereby blocking or limiting flow of the corresponding liquid upwardly through thoseholes of the trough which are not aligned with the groove of a die. This reduces the liow required in the liquid supply channel below the trough, thereby limiting overflow of the liquid. Preferably, keys are provided to secure the plug means against rotation with the shaft, and the keys adjacent exposed end faces of the dies also effect a wiping action to prevent the film-forming liquid from accumulating on these faces.

These and other features of the invention will bebetter understood by reference to the accompanying drawings illustrating a preferred. form of the apparatus. In the drawings: y

FIG. l is a diagrammatic plan view of the apparatus, illustrating certain principles involved;

:titres FIG. 2 is a :plan view of the apparatus on a larger scale;

FIG. 3 is a vertical section on the line 3-3 of FIG. 2, but showing a modified form of the means for supplying the coating liquids to the applicators;

FIG. 3a is a vertical section on the line 3ft-3a of FIG. 2; l

FIG. 4 is a vertical section on the line 4 4 of FIG. 3;

FIG. 4a is avertical section on the line la-4a of FIG. 3;

FIG. 5 is a vertical section on the line 5 5 of FIG. 2; Y

FIG. 6 is a detaill perspective view of a portion of one applicator, accommodating three wire passes, showing one applicator die and two bypass die spacers;

FIG. 7 is a vertical section on the line 7-7 of FIG. 3;

FIG. 8 is a vertical section .on the line 8-8 of FIG. 7;

FIG. 9 is a detail plan View of portions of the apparatus for processing a single wire strand by the application of a nu-mber of successive coats each dried before the next is applied, some of which coats may be of a different material from others; t

FIG. 10 is a detail plan view of certain applicator elements;

FIG. ll is a vertical section on the line 1-1--11 o FIG. 10; and

FIG. 12 is a schematic perspective view of the left side of the machine, as viewed in FIG. 2, showing certain drives.

I have shown schematically in FIG. 1 a system embodying my invention in which a number of coats of different film-forming materials are applied to a bare wire, with provision -for'passage of the wire through a drying oven Y'between successive coats. At 2 is a AWire supply reel from which the bareV wire 4 is drawn and `passed over .the coating applicators 6 and 8 at the A position at one end of the machine, after whichthe Wire passes through the drying oven 10, around the` return roll 12, over the applicators 16 and 14 at the B position on the farV end of the machine, and thence returning throughthe oven. For illustrative purposes, assume that a number of coats of one hlm-forming material, typically Formvan polyurethane or a similar dielectric material, are to be applied, followed by a number of coats of a nish film-forming material such as Bondeze, nylon, or the like, with an oven pass between each coating. VThe system, employing the dual applicators 6 and 8 at one end of the machine and 14 and` 16 at the .other end, wou-ld be supplied, as will be described, with the undercoating dielectric material in applicators 6 and 16 f and with the inish coating material in applicators 8 and I4. I have shown a system in which four undercoats of the dielectric are applied followed by two coats of the finish material.` Thus, the wire of pass 4a leaving the station A has a coating of dielectric applied by the applicator 6', which is dried by passage of the wire through oven lil, after which the wire with the dried coat passes over applicator 16 on the return pass 4b, where it receives its second coat of dielectric and passes over applicator 14 without receiving a coat. Thence the wire pass 4b advances through the oven 10 and underneath theapplicators 8 and V6 at the A position.

In FIG. 5,:the relative vertical positions of the elements are shown indicating the wire 4 receiving a coat at applicator .6, passing over. applicator S without receiving `a coat, thence through oven It), and around return roll 12 to receive a coat at applicator 16, but with a dry pass over the applicator 14. Thence the wire passes through oven 1li and beneath applicators 8 and 6 at the A station. The wire then returns around roll 18, as pass 4c, to receive the third insulating coat at applicator 6, with a dry pass over :applicator 8, and thence through oven itl, around roll 12, to receive, as pass 4d, its nal dielectric coat at applicator 16. The pass 4d, after traversing oven -10 and returning around roll l, receives as pass 4e its iirst coat of iinish film at applicator 8, having bypassed applicator 6, and after that coat is dried and the wire returns around roll l2, it receives, as pass tlf, its inal finish coat at applicator 14, from which the wire passes through the oven 1G' to a driven windup spool El? of finished wire. The windup spool 24), supply spool 2 and return rolls l2 and 13 form av means for moving the wire lengthwi-se in multiple passes back and forth through the oven; from one end to the other.

It is to be observed that by this system any number of coats of one insulating varnish or enamel maybe applied, followed by a series of coats of a dissimilar varnish or enamel, with a drying pass between each coat; and although each coat is dried before it passes around the return roll, there are no idle or useless passes of the wire through the drying oven (i.e., there are six passes through the oven for six separate coats), thereby substantially enhancing the ei'lciency of the apparatus.

The operation for treating wire 4 from supply reel 2, involving the several passes described, is the function of the stage of the machine designated I in FIG. l and is simultaneously performed on another wire, as at stage Il, and 4for as manyother wires as will eliciently use practicable lengths of applicators and oven. v

In FIG. 2, the parts corresponding to the diagram are correspondingly numbered. Roll 18 is shown at one end of the machine and the rolllZ at the other. The applicators 6 and S at the A position at one end of the oven are shown, as are the applicators 14 and 16 at the B position at the opposite end of the oven. The supply spools 2 and the finish spools 29 are omitted for clarity. I have shown in FIG. 9 that portion of the apparatus of FIG. 2 needed for complete processing of one strand of wire conforming to stage I in FIG. l. The six passes, 4a through 4f, are indicated.

'I'he applicators 6, 8, 14 and 16 are basically in Iall respects identical in construction, differing only in certain manual adjustments and part replacements by which the applicator may be adapted for applying coating during certain of the passes and allowing the wire to bypass the applicator without application of coating during other passes. As typifying the construction, FIG. 6 shows the stage I portion of applicator 14, at the B position, with its parts arranged so that the Wire will bypass the applicator during passes 4b and 4d and will receive a coat during pass 4f, these locations being designated, respectively, 60, 32 yand 34.

Each of the applicators is in the form of an elongated `block 36 suitably secured in relation to the oven and having a longitudinal channel 3S to which the corresponding hlm-forming liquid (wire enamel or varnish) is conducted from a supply source. Each block 36 has a series of slots 4t)` constituting wire guides to direct the Wire to the individual die or bypass location. At 42 is a halfround section of tube forming a trough having a series of apertures 44 communicating with the underlying channel 38. The trough 42 is suitably mounted and secured to conformingly arcuate surfaces of the block 36 above the channel 38. The supply of coating liquid is under a l suiiicient pressure or head, as will be explained, to

provide a flow rate of the liquid adequate to keep the circumferential grooves of the revolving dies full of liquid, one of these dies being shown at 501 in FIG. 6.

The die 50 shown in FIG. 6 is mounted on a driven shaft or die rod 52 and is Iin the form of a disc having a relatively Wide circumferential channel or groove 54 formed in its peripheray and having in the bottom of this groove a relatively narrow circumferential groove 54a of triangular cross-section which the Wire 4, in this instance the pass 4f, engages as it moves over the rotating die in the direction indicated by the arrow. The 'applicator is provided in proximity to each of -the dies S0 With the usual die finger 7d (best shown in FIGS. l0 and 1l) extending from a plate or bar 72 secured to the applicator block 66 by screws 74. The latter are received in screw threaded holes 76 (FIG. 5) in the block portions 78 delineating the guide slots 40. rlfhe wire passes through the correspondingk aligned slot 40 under the bar 72 and then over the die in its peripheral narrow groove 54a, where the wire is conned by the overlying nger 70 which serves to wipe the excess liquid from the wider groove 54.

Each drive shaft or die rod 52 is mounted for rotation on the axis of the trough 42 of the corresponding applicator 6, 8, 14 or 16. Where the wire pass is to receive a coating from the applicator (as at location 34 in FIG. 6), the corresponding shaft 52 carries a die 50` as` previously described; and where the wire pass is to bypass the applicator (as at locations 30 and 32 in `FIG. 6), the shaft carried a die spacer 60 in the form `of a spool having end flanges 61 (FIGS. 4-6 and l0). `The spacers 60 including their flanged ends 61 are substantially smaller in diameter than the dies 50 so as to prcvide voids for bypassing the wire 4. The dies 50 and spacers 60 are connected to shaft 52 for rotation therewith. Any desired arrangement may be provided 'for this purpose, such as a nut (not shown) on one end of the shaft which clamps the dies and spacers together against a shoulder (not shown) on the other end of the shaft. As a further example, I have shown the shaft 52 formed with a keyway 53 (FIG. 6) by which each die 5G and spacer 60 may be keyed to the shaft through a key 55 (FIG. l1).

The dies 50 and spacers 60 abut endwise against each other on the shaft 52. The entire assembly of dies and die spacers is held against longitudinal displacement on shaft 52 between end members 80 secured to the opposite ends of 'block 36 Iby screws 82 (FIGS. 2, 3, 3a and 4a).

These end members 80 are suitably supported and positioned by frame plates 814 mounted on the frame proper 86. Thus, as to each of the applicators 6, 8, 14 and 16, each of its dies 50 is held in alignment with a corresponding slot 40 and in position to apply a coating to the wire passing through such slot, which each of its spacers 60 is held in alignment with a corresponding slot 40 and in position to provide a void for bypassing the wire passing through such slot.

Each spacer means 60 overlies a semi-circular plug means 62 located in the trough 42 and covering the corresponding aperture 44 in the bottom of the trough. Each plug 62 has a close fit against the semi-cylindrical inner surface of the trough 42 and against the semicylindrical under surface of the corresponding spacer 60, the width of the plug being such that it tits closely between the end anges 61 of the spacer. To insure against its rotation with shaft 52, each plug 62 is provided with a key or clip 64 in the -form of a thin metal strip having 'intermediate its ends an arcuate portion fitting closely around the semi-cylindrical upper surface of the correspending spacer 60'. The end of this key nearest the aligned slot 40 of the corresponding applicator lies against the upper surface of the corresponding plug 62 and terminates short of the adjacent edge of trough 42 (FIGS. 4 5), while the other end of the key 64 extends along the upper surface of the plug and protrudes over the opposite edge of trough 42, against .which it abuts (FIGS. 4-6). The direction of rotation of the corresponding shaft or die rod 52 is such as to urge this protruding end of key 64 against the underlying edge of trough 42 (FIG. 6), whereby the key and the latter edge coact as a stop toprevent rotation of the underlying plug 62.

Each, key 64 fits closely between the end lianges 61 of the corresponding spacer 60 and is releasably secured to the underlying plug 62, as by screws 64a. Because of this, each key 64 adjacent a die S0 will have anedge closely spaced from the adjacent end wall of the die, thereby acting as a wiper to prevent build-up of coating liquid on this exposed end wall of the rotating die.

As will be described in more detail presently, the func tion of the plugs 62 is to lill the trough 42 below the spacers 68 and thus block flow of liquid upwardly from the corresponding trough holes 44 and laterally and upwardly` from the small clearance spaces between adjacent dies and the trough, it being understood that the trough has a hole 44 aligned with each slot 40 and underlying either a plug 62 or the circumferential groove 54 of a ldie 50.

coatings to a number of wire supplies at stages I, II, etc.

In each applicator 6, 8, 14 and 16, the shaft or die rod 52 is mounted for rotation in suitable bearings 81 secured in the end members 80, the shafts beingl driven in any suitable manner ata uniform speed and in the directions shown by the arrows in FIG. 5. A suitable driving mechanism, shown in FIGS. 2, 3 land l2, comprises a main drive shaft 100 to which power is supplied from a source, not shown. Shaft 100 carries a pulley 102 around which belt 104 is trained to drive a pulley 186 on shaft 52 of applicator 14 (FIG. l2). The latter shaft carries another pulley 108 which, through belt 110 and pulley 112, drives shaft 52 of applicator 16 in the same direction as the shaft of applicator 14. 'I'he shaft 52 of applicator 14 also carries a third pulley 114 which, by a reverse belt 116, drive pulley 118 on shaft 52 vof the applicator 8. The latter shaft carries another pulley 120 which, through belt 122 and pulley 124, drives shaft 52 Y of applicator 6. Thus, the shafts 52 of applicators 6 -and 8 are driven in a direction opposite to that of shafts 52 of applicators 14 and 16.

The channels 38 of the applicators 6,8, 14 and 16 are each supplied with the desired coating liquid to be applied to the wire by the respective dies S0. The desired coating liquid is supplied continuously to each channel 38 at a rate suiiicient to replace the liquid coated on the wire by the corresponding dies and' keep the revolving die grooves full of coating liquid. Thus, the dies 50 thoroughly coat the'wire passing through their corresponding circumferential grooves 54a, the wire being pulled by the windup spool 20, and if necessary by the rolls 12 and 18, at the proper linear speed to receive the coating, as will be readily understood by those skilled in the art.

As shown in FIG. 3, a liquid supply pipe 130 has two valved branches 132 and 134 leading, respectively, to the channels 38 of two stages of the -applicator block 36, by way of a divider 136 between the two stages. The divider 136 and block 36 are suitably ported to convey the liquid from branch pipes 132 and 134 to the respective channels 38, as shown at 133 and 135 in FIGS. 7 and 8. Alternatively, the end members 80 may be ported to supply the desired coating liquids to the respective channels 3S from pipes 138a through 1380! and 14811 through 1401i, as shown in FIG. 2. In either case, the channels 38 of applicators 6 and 16 are supplied with the liquid for the undercoats on the wire, and the channels 38 of applicators 8 and 14 are supplied with the liquid for the nish coats.

In the operation of the illustrated apparatus, rotation of the dies 50 in each applicator acts to depress the liquid level adjacent the forward edge of the trough 42 which underlies the protruding ends of keys 64, that is, the trough edge toward which the upper portions of the dies are moving. Conversely, such rotation of the dies acts to raise the liquid level adjacent the rear edge of the trough 42 nearest the slots 40. The plugs 62 serve to block or limit the flow of liquid upwardly under pressure from the underlying channels 38, thereby avoiding excessive overflow of liquid from the upper edges of the troughs 42. Such overflow as does occur is collected in La trough-shaped receptacle 142 secured below each block 36 (FIGS. 2-5) and, through pipe 144 leading from the 4bottom of this receptacle, is drawn of for re-use, as by returning it to the liquid. supply source. The liquid removed as coating on the wire and as overflow is constantly replenished from the liquid supply means or 138a-138d and 14001-1400?.

It will be apparent, therefore, that the new apparatus provides Jfor coating the wire with two diierent fil-mforming materials, with the use of only one oven and with no sacrifice in oven capacity, all of the liquid coatings receiving identical exposure in the oven. This is true whether the coatings are applied at both ends of the oven, as illustrated, or at only one end. 'in the latter case, each coating will pass twice throu-gh the oven, instead of only once, before application of the next coating. More than two different coating materials may be applied to the wire, of course, by providing the appropriate number of applicators. Also, by adjusting the order of the dies 50 and spacers 6i? along the die shafts 52.0f the respective applicators, any desired coating sequence can be obtained. Thus, the apparatus can be readily adapted for carrying out different coating procedures.

The spacers 160 and associated plugs 62 constitute means for avoiding any contact with the wire (by an applicator or the liquid coating material therein or otherwise) except at a die 50 as the wire passes to the oven from the returned roll 12 or 18. This is of advantage generally but is particularly important in preventing any contact with the wire after it has received a coating from one of the' applicators 6 and 16 and before it has passed through the oven to the next return roll. That is, any contact at applicator 8 or 14 of an unbaked coating appliedto the wire by applicator 6 or 16, respectively,

lwould impair such coating. In addition, the plugs 62,

by substantially coniining the coating liquids to the dies 50 in the respective applicators, avoid excessive overflow of the liquid and reduce the rate at which the liquidmust be supplied to the channels below the troughs.

If desired, after assembly of the apparatus as described and illustrated, a cover 150 in the shape of an inverted trough may be secured to each' applicator over its trough 42 (FIG. 4) to further confine the coating liquid. This coverhas openings (not shown) for passage for rthe wire from the slots 40 and for receiving the die fingers 70, one edge of the cover being spaced from the underlying edge of trough 42 to form a slot or keyway 152for the keys 64, as shown in FIG. 4.

I claim:

1. In a wire coating apparatus, the combination of an` f moving to the oven and adapted to receive a coating liquid different from the liquid in the other applicator channel, each applicator also including a driven shaft extending along said channel and at least one disc-shaped die mounted on and rotated by said shaft in position to be immersed in the liquid in the corresponding channel and to apply at the peripheral portion of the die a coating of said liquid to an overlying pass of said series, and spacer means mounted on each shaft and located below each pass of said series Which is coated by a die on the other shaft, the spacer means forming voids through which the passes of said series are adapted to move without contacting the corresponding applicator or liquidiherefrom. 'f

2. The combination dened in claim 1, in which each applicator also includes a trough mounted in said channel above the bottom thereof, the trough having holes approximately underlying the passes of said series, respectively, each die having its lower portion fitting closely in the corresponding trough land having a circumferential groove adapted to receive coating liquid from an underlying one of said holes, the combination comprising also` plug means located in the troughs below the corresponding spacer means to cover said holes other than the holes underlying the dies.

. f 3. The combination deiined in claim l, in which each applicator also includes a trough mounted in said channel above the bottom thereof, the trough having holes approximately underlying the passes of said series, respectively, each die having its lower portion iitting closely in the corresponding trough and having a circumferential groove adapted to receive coating liquid from an underlying one of said holes, the combination comprising also plug means'located in the troughs below the corresponding spacer means to cover said holes other than the holes underlying the dies, the plug means substantially lling the troughs below the respective spacer means.

4. The combination defined in claim 1, in which each applicator also includes a trough mounted in said channel above the bottom thereof, the trough having `holes approximately underlying the passes of said series, respectively, each die having its lower portion fitting closely in the corresponding trough and having a circumferential groove adapted to receive coating liquid from an underlying one of said holes, the combination comprising also plug means located in the troughs below the corresponding spacer means to cover said holes other than the holes underlying the dies, the plug means sub- Y stantially filling the troughs below the respective spacer means, and keys holding the plug means against rotation with the shafts relative to the troughs.

5. The combination delined in claim l, in which each applicator also includes a trough Ymounted in said channel above the bottom thereof, the trough yhaving holes ap-` proximately underlying the passes of said series, respectively, each die having its lower portion tting closely in the corresponding trough and having a circumferential groove adapted to receive coating liquid from an underlying one of said holes, the combination comprising also plug means located in the troughs below the corresponding spacer means to cover said holes other than the holes underlying the dies, the plug means substantially lling'the troughs below the respective spacer means, and keys holding the plug means against rotation with the shafts relative to the troughs, the keys fitting around the upper portions of the spacer means and each having an end portion engaging an edge of the corresponding trough. f

6. The combinataion defined in claim l, in which each applicator also includes a trough mounted in said channel above the bottom thereof, the ltrough having holes approximately underlying the passes of said series, respectively, each die having its lower portion fitting closely in the corresponding trough and having a circumferential groove 'adapted to receive coating liquid from an underlying one of said holes, the combination comprising also plug means located in the troughs below the corresponding spacer means to cover said holes other than the holes underlying the dies, the plug means substantially iilling the troughs below the respective spacer means, and keys holding the plug means against rotation with the shafts relative to the troughs, the keys fitting around the upper portions of the spacer means and each having an end portion engaging an edge of the corresponding trough, some of said keys each having an edge `adjacent one end of a die and serving as a wiper for said die end.

7. The combina-tion deiined in claim l, comprising also a second pair of coating applicators located adjacent the opposite end of the oven and below a second series of siad passes moving lto the oven, the applicators of said second pair being applicators constructed as dened in claim l and being operable to coat passes of the second series in the manner that passes of the first series are coated by the rst pair of appiicators.

8. In a wire coating apparatus, the combination of au oven, means for Vmoving a Wire lengthwise in multiple passes back and forth through the oven from end to end thereof, a pair of coating applicators adjacent the oven at one end thereof and located below, and in position to apply liquid coatings to, a series of said passes moving to the oven, a second pair of coating applicators adjasite' cent the oven at the opposite end thereof and located below, and in position to apply liquid coatings to, a second series of said passes moving to the oven, pipes leading to one applicator of each pair for supplying thereto a first coating liquid, and pipes leading to the other applicator of each pair for supplying thereto a second coating liquid, each applicator of each pair including at least one die yfor applying a coating of the corresponding liquid to a wire pass of the corresponding series and forming a bypass space for passage of each wire pass coated by a die of the other applicator of said pair.

9. The combination according to claim 8, in which each applicator also includes a block having a channel for receiving coating liquid from the corresponding supply pipe, a driven shaft extending along the channel above the bottom thereof and below the corresponding series of passes, each corresponding die being driven by the shaft and mounted thereon in position to be immersed in the liquid inthe channel, and spacer means ou the shaft forming each bypass space.

l0. A wire coating applicator comprising an elongated trough, a driven shaft vextending lengthwise of the trough above the bottom thereof, the wall of the trough having a series of holes spaced along the length of the trough, liquid supply means communicating with said holes and operable to supply a coating liquid through the holes to the interior of the trough, a plurality of disc-shaped dies mounted on the shaft for rotation therewith in position .'to be immersed in said liquid in the trough, each `die having its lower portion 'litting closely in the trough and having a circumferential groove aligned with one of said holes, whereby the dies are adapted to coat simultaneously with said liquid a plurality of respective wire passes moving overthe dies through their respective grooves, the trough having some of its holes located out of alignment with the dies, and spacer means mounted on the shaft above said last holes which are not aligned with the dies, the spacer means forming spaces through which wire passes bypassing the applicator are adapted to move.

1l. An applicator as dened in claim 10, in which the dies and spacer means are removably mounted on the shaft, the spacer means abutting the dies and holding them against endwise displacement on the shaft.

l2. A wire coating applicator comprising an elongated trough, a driven shaft extending lengthwise of the trough above the bottom thereof, the wall of the trough having a series of holes spaced along the length of the trough, liquid supply means communicating with said holes and operable to supply a coating liquid through the holes to the interior of the trough, a plurality of disc-shaped dies mounted on the shaft for rotation therewith in position to be immersed in said liquid in the trough, each die having its lower portion fitting closely in the trough and having a circumferential groove aligned with one of said holes, whereby the dies are adapted to coat simultaneously with said liquid a plurality of respective wire passes moving over the dies through their respective grooves, the trough having some of its holes located out of alignment with the dies, and plug means removably mounted in the trough opposite said last holes which are not aligned with the dies, the plug means substantially filling those parts of the trough not occupied -by the dies.

13. A wire coating applicator comprising an elongated trough, a driven shaft extending 'lengthwise of the trough above the bottom thereof, the wall of the trough having a series of holes spaced along the length of the trough,

liquid supply means communicating with said holes and operable to supply a coating liquid through the holes to the interior of the trough, a plurality of disc-shaped dies mounted on the shaft vfor rotation therewith in position to be immersed in said liquid in the trough, each die having its lower portion fitting closely in the trough and having a circumferential groove aligned with one of said holes, whereby the dies are adapted to coat simultaneously with said liquid a plurality of respective wire passes moving over the dies through their respective grooves, the trough having some of its holes located out of alignment with the dies, and plug means removably mounted in the trough opposite said last holes lwhich are not aligned with the dies, the plug means substantially filling those parts of the trough not occupied by the dies, and spacer means mounted on the shaft above the plug means and forming spaces through which wire passes bypassing the applicator are adapted to move.

14. A wire coating applicator comprising an elongated trough, a driven shaft extending lengthwise of the trough abovev the bottom thereof, the wall of the trough having a series of holes spaced along the length of the trough, liquid supply means communicating with said holes and operable to supply a coating liquid through the holes to the interior of the trough, a plurality of disc-shaped dies` mounted on the shaft for rotation therewith in position to be immersed in said liquid in the trough, each die having its lower portion fitting closely in the trough and having a circumferential groove aligned with one of said holes, whereby the dies are adapted to coat simultaneously with said liquid a plurality of respective wire passes moving' over the dies through their respective grooves, the trough having some of its holes located out of alignment with the dies, and plug means removably mounted in the trough opposite saidlast holes which are not aligned with the dies, the plug means substantially filling those parts of the trough not occupied by the dies, spacer means mounted on the shaft above the plug means and forming spaces through which wire passes bypassing the applicator are adapted to move, and key means securing the plug means against rotation with the shaft relative to the trough.

l5. A wire coating applicator comprising an elongated trough, a driven shaft extending lengthwise of the trough above the bottom thereof, the wall of the trough having a series of holes spaced along the length of the trough, liquid supply means communicating with said holes and operable to supply a coating liquid through the holes to the interior of the trough, a plurality of disc-shaped dies mounted on the shaft for rotation therewith in position to be immersed in said liquid in the trough, each die having its lower portion lfitting closely in the trough and having a circumferential groove aligned with one of said holes, whereby the dies are adapted to coat simultaneously with said liquid a plurality o-f respective wire passes moving over the dies through their respective grooves, the trough having some of its holes located out of alignment 'with the dies, plug means removably mounted in the trough opposite said last holes which are not aligned with the dies, the plug means substantially filling those parts of the trough not occupied by the dies, spacer means mounted on the shaft above the plug means and forming spaces through which wire passes bypassing the applicator are adapted to move, and key means securing the plug means against rotation with the shaft relative to the trough, the key means including edge portions located adjacent ends of the dies to wipe coating liquid from said ends.

References Cited in the tile of this patent UNITED STATES PATENTS 

